Membrane sealed pistonphone

Abstract

The invention discloses a membrane sealed pistonphone, comprising a cavity, a piston and a support base for supporting the cavity. The piston and the cavity are coaxial. One end of the cavity is an opening end. The other end of the cavity is equipped with an end plate. A mounting hole is arranged on the end plate. The piston is located at the opening end of the cavity. Sealing membrane seals the opening of the cavity to form a sound production cavity. The sealing membrane is elastic. The sound production end face of the piston fits the sealing membrane. A pressure balancing hole is arranged on the cavity. The pressure balancing hole is communicated with the outside world and the sound production cavity. The pressure balancing hole is arranged on the end plate. A mounting hole is used for mounting a calibrated sensor. The membrane sealed pistonphone has the advantages that the cavity is sealed by the sealing membrane to form the sound production cavity; the cavity is communicated with the air of the outside world only through the set pressure balancing hole; a static pressure balancing mechanism is realized; the aperture of the pressure balancing hole is very thin, so the sound production cavity has a relatively large time constant; and the lower limit working frequency of the pistonphone is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of acoustic measurement, and relates to a piston sounder. [0002] technical background [0003] A microphone is an energy conversion device that converts sound signals into electrical signals. It is an important link in the electroacoustic system and is widely used in many fields such as vocal music, communication, and aerospace. In order to ensure that the output signal of the microphone is accurate and effective, according to the provisions of the measurement verification regulations, the sensitivity, frequency response and other performance indicators of the microphone must be calibrated before leaving the factory or after a period of use. [0004] The piston sounder is an important device to realize the calibration of the sound pressure sensitivity of the microphone. It drives the piston to do sinusoidal vibration with a given frequency and amplitude through the excitation device, and forms a sound field...

AI Technical Summary

Problems solved by technology

However, the gap between the piston and the cavity is one of the difficulties in the design of the piston sounder. The main reasons are: 1) If the gap is too small, during the reciprocating movement of the piston, it is easy to generate friction with the cavity, resulting in friction noise The displacement waveform output by the piston and the piston is distorted (that is, it is not an ideal sine wave), which in turn causes the sound pressure signal to be distorted; 2) If the gap is too large, the gap between the piston and the cavity forms a flow channel for the gas medium, which will cause Leakage of sound pressure in the cavity, resulting in sound pressure leakage error, and the lower the operating frequency of the piston sounder, the greater the leakage error

Due to the limitation of the gap seal, the gap-sealed piston sounder cannot reach a lower lower limit operating frequency

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